1. Field of the Invention
The present invention relates to a digital broadcasting system, and more particularly, to a device and method for controlling an operating mode of an application included in service data which is transferred together with a broadcast program.
2. Description of the Related Art
Information processing speed is increasing due to the development of personal computers (PCs), and information transmission speed is also improving due to the spread of the Internet. As a result, PCs may either coexist with TVs, or PCs and TVs may be integrated. The combination of a PC and a TV can be achieved by integrating TV functions into a PC or by integrating PC functions into a TV. These two types of combinations have already been partially accomplished. Reception cards for Internet TVs or PC TVs have been developed and used. However, it is still considered that these combinations do not employ sufficiently the merits of the two media.
Digital TVs, which have been developed to overcome the complaints about existing analog TVs, can provide multiple channels and a high image quality compared to the analog TVs, and several functions that cannot be provided by analog TVs. In particular, broadcasting of multimedia data together with programs constituted of video and audio has allowed TVs to provide various types of multimedia data services.
That is, digital TV techniques are developed to techniques for providing various data services based on current high quality of image and high quality of sound, and the data service is moving from one-way services toward interactive services using a two-way channel.
The types of services that can be provided by this type of data broadcasting can be roughly classified into data services related to particular programs, independent data services, and interactive data services. The characteristics of each service type will now be described.
For data service related to a particular program, information associated with a program being currently broadcast is transmitted together with a broadcast signal (e.g., an audio signal, a video signal or the like). Here, the information includes information associated with the sports relay broadcast (e.g., player record information, sports terms, game rules, main event information, and so on), additional information on soap operas, additional information on a commercial being currently broadcast, and others.
For independent data services, independent information not related to a program being currently broadcast is sent together with a broadcast signal, and then the independent information is displayed on a screen upon demand by a viewer. Here, the independent information includes information such as real time news, weather forecasts, stock market quotations, software downloads, electronic coupons, and web contents. The independent data service can provide an interactive service which faithfully employs multimedia, since it can use not only simple texts, but also applications such as hypertext, graphics, images, animations, audio/video clips, and Java applets. For example, while a basketball game is being relayed, detailed information on a particular player can be displayed on one area of a TV screen, or a past scene where the player's plays can be provided through a video clip.
For interactive data service, the input of a viewer is transmitted to a broadcast company, and the viewer can be provided with a broadcast service corresponding to his or her input. After viewers establish an environment capable of receiving the two-way data service by securing a two-way channel using a modem, a leased circuit or the like, they can be provided with services such as public opinion polls, voting for ranking popular songs, audience rating surveys, popularity votes, question surveys, home shopping, or the like. Also, various other interactive services can be accomplished by connection with external information providers.
The data service connected with a particular program, and the independent data service are generally achieved through a one-way service such as a data broadcast. However, a data carousel system for repeatedly providing data having an effective period is additionally used to enable the interactive service at any time in the middle of the one-way data service.
FIG. 1 illustrates the reception, from a broadcast station by a digital broadcast receiver (e.g., a digital TV), of program A and service data associated with program A (e.g., an application or the like), which is transmitted by the data carousel method. As can be seen from FIG. 1, a digital TV repeatedly receives service data related to program A while receiving and outputting an audio/video signal associated with program A.
These interactive services can be realized by HTML, Java, data service protocol techniques or the like. The HTML technique is used to express data being provided on a screen, and the Java technique is used to secure the reproduction of broadcast contents independent of the type of hardware and operating system of a receiver. Thus, the contents of a data broadcast are an HTML application and a Java application. The HTML and Java applications can include various types of texts, audio data, video data, and graphic data.
The data service protocol is a standard for including these contents in a broadcast signal constituted of a moving picture experts group-2 transport stream (MPEG-2 TS).
The Advanced Television Systems Committee (ATSC) in U.S.A. and the Digital Video Broadcasting (DVB) in Europe have established related standards to support these enhanced/interactive broadcast services.
ATSC is an organization for establishing standards for digital TV related techniques in the U.S.A. In particular, technical groups such as T3/S13 (data broadcasting), T3/S16 (interactive services), T3/S17 (DTV applications software environment: DASE), and data implementation work group (DIWG), establish data broadcast related standards.
T3/S17 (DASE) defines standards related to software structures within digital TV receivers for supporting a data service, T3/S13 (data broadcasting) defines data service protocols, and T3/S16 (interactive services) defines standards for two-way services using digital broadcasting. The definition of a session protocol for the two-way service, and a definition of a system structure including the operation and performance required for a two-way data channel, are being discussed with a high priority.
However, T3/S13/S16 defines only a method of transporting an application, and does not define a method of setting a point of time when an application starts. Hence, an application received by a digital broadcast receiver is supposed to be executed only when demanded by a viewer. That is, the application received by a digital broadcast receiver can be executed only when a viewer executes the application clearly.
However, there are applications that must be executed immediately after being received. For example, an application which functions in relation to a broadcast itself, or an application such as urgent news, must be executed immediately after being received, independent of the selection of viewers. As described above, a conventional digital broadcast system cannot provide a variety of services which consider the operating mode of an application which is additionally transmitted.